Electrochemical Detection of Hg(II) in Environmental Water Samples Based on Multiwalled Carbon Nanotube–Reduced Graphene Oxide Hybrid Film

Abstract

In this work, we describe the fabrication of an electrochemical sensor for the detection of Hg²⁺in various water samples. The electrochemical sensor is fabricated on an indium tin oxide (ITO) modified with multi–walled carbon nanotubes (MWCNT) and reduced graphene oxide (RGO) hybrid film. The MWCNT was firstly dispersed using graphene oxide (GO) as dispersant. After coating on the ITO, the GO was then electrochemically reduced to RGO. The obtained thin film was characterized by scanning electron microscope (SEM), FTIR, Raman spectroscopy and 3D optical surface profiler. Cyclic voltammetry and differential pulse voltammetry were employed to investigate the electrocatalytic performance towards the Hg²⁺ oxidation. Under optimum conditions, the proposed sensor showed a wider linear range at Hg(II) concentrations of 0.05–150 nM. The limit of detection was calculated to be 0.05 nM.